1998 a6 2.8 head/engine questions atq vs aha
12-09-2012, 11:41 AM
#1
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1998 a6 2.8 head/engine questions atq vs aha
Okay, so i recently, in the past 10 minutes, realized that my motor has one aha head, and one atq head. The history on this vehicle i know of is, my boss bought it not running with a bad head on passenger side. I dont think he knew when he purchased a used head for it that he was purchasing an atq head instead of an aha head, like the rest of the aha engine. My question is, what is the difference between the atq and aha head. I know the atq and aha engine have different compression ratios, but im curious if that is judged by the gaskets, pistons, or combustion chamber volume. Also is there any difference in the camshaft profiles between the two. I know he put a loaded head on it, nothing was swapped off the old aha head. Ive been working on a 2001 a4 2.8 with the atq, and the car runs so much stronger than mine, and im also still trying to hunt down why my car has the vibration/performance problems it does. No one at my work, including my boss, ever drove this car before it was brought in not running, but the person who owned it before him was pretty meticulous with fixing everything the right way, so im curious as to what affect this may be having on my engine and its performance.
12-09-2012, 05:26 PM
#2
False. The only difference between ATQ and AHA is drive by wire versus drive by cable. The specs on the heads are the same.
If your car is not showing any codes, start by checking/setting exhaust cam timing.
If your car is not showing any codes, start by checking/setting exhaust cam timing.
12-09-2012, 06:06 PM
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if vagcom shows me, what am i looking for ? I know i sound clueless, but im trying to narrow down what im looking for, or have some education before i jump in. I can get access to vagcom but i need to know what to look for.
12-09-2012, 06:13 PM
#6
12-09-2012, 06:14 PM
#7
1. Read up on doing a timing belt service. The adjustment is part of the service
2. Obtain the timing belt bar and pin
3. Install the pin to lock the crank in place.
4. Using the locking bar to steady one cam at a time, loosen each cam sprocket bolt about two turns.
5. Use a puller or sharp hammer blow to the bolt head to pop each sprocket free of the cam
6. Install the locking bar, turning cams a little as required to install it (this is the adjustment part)
7. re-tighten sprocket bolts to lock the sprockets back on the cams. Start with bank 2 (driver's side in the US)
8. Re-assemble car and enjoy the increased power and fuel economy
2. Obtain the timing belt bar and pin
3. Install the pin to lock the crank in place.
4. Using the locking bar to steady one cam at a time, loosen each cam sprocket bolt about two turns.
5. Use a puller or sharp hammer blow to the bolt head to pop each sprocket free of the cam
6. Install the locking bar, turning cams a little as required to install it (this is the adjustment part)
7. re-tighten sprocket bolts to lock the sprockets back on the cams. Start with bank 2 (driver's side in the US)
8. Re-assemble car and enjoy the increased power and fuel economy
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12-09-2012, 06:18 PM
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Okay so back to checking/setting the exhaust cam timing. How is that done? Obviously by setting some cylinder to tdc and counting teeth im assuming or aligning something but i have no access to literature to specify and no thread i can find has a concrete answer, just a bunch of people in a pissing match on unspecific details. I'm appreciative to any concrete/specific information that can be provided aiding me in checking this, because im confident that something, somewhere along the line, wasnt quite set right when this head was put on. Dont get me wrong, the car runs decent, but it doesnt run anywhere close to how i feel it should, especially after driving a customers 2.8, i feel like mine has a completely different engine.
12-09-2012, 06:20 PM
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1. Read up on doing a timing belt service. The adjustment is part of the service
2. Obtain the timing belt bar and pin
3. Install the pin to lock the crank in place.
4. Using the locking bar to steady one cam at a time, loosen each cam sprocket bolt about two turns.
5. Use a puller or sharp hammer blow to the bolt head to pop each sprocket free of the cam
6. Install the locking bar, turning cams a little as required to install it (this is the adjustment part)
7. re-tighten sprocket bolts to lock the sprockets back on the cams. Start with bank 2 (driver's side in the US)
8. Re-assemble car and enjoy the increased power and fuel economy
2. Obtain the timing belt bar and pin
3. Install the pin to lock the crank in place.
4. Using the locking bar to steady one cam at a time, loosen each cam sprocket bolt about two turns.
5. Use a puller or sharp hammer blow to the bolt head to pop each sprocket free of the cam
6. Install the locking bar, turning cams a little as required to install it (this is the adjustment part)
7. re-tighten sprocket bolts to lock the sprockets back on the cams. Start with bank 2 (driver's side in the US)
8. Re-assemble car and enjoy the increased power and fuel economy
12-09-2012, 06:58 PM
#10
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